Machine gun magazine and cradle therefor



April 1947. G. AQCHADWICK ETAL 2,418,462

MACHINE GUN MAGAZINE AND CRADLE THEREFOR Filed May 22, 1936 5 Sheets-Sheet 1 5 Sheets-Sheet 2 I FF/11111111111111;

L A n K m w D A H C G MACHINE GUN MAGAZINE AND CRADLE THEREFOR Flled May 22, 1936 Aprii 8,, 1947. G. A. CHADWICK EIAL 2,418,462

MACHINE GUN MAGAZINE AND CRADLE THEREFOR Filed May 22, 1936 5 Sheets-Sheet 3 April 8, H947. G. A. CHADWICK ETAL 2,418,452

MACHINE GUN MAGAZIIYE AND CRADLE THEREFOR Filed May 22, 1936 5 Sheets-Sheet 4 April 8, 1947.

G. A. CHADWICK ETAL MACHINE GUN MAGAZINE AND CRADLE THEREFOR Filed May 22, 1936 5 Sheets-Sheet 5 Patented Apr. 8, 1947 UNITED STATES PATET OFFICE MACMNE GUN MAGAZINE AND'CRADLE THEREFOR George A. Chadwick and Paul W. Burk, Washington, D. 0.

15 Claims.

This invention relates to means for continuously feeding ammunition to a machine gun and has among its numerous objects to provide an improved magazine and a mounting therefor that will automatically move an empty magazine from the feeding position and replace it with a full magazine, prevent the ready removal of a full magazine from the mounting, automatically unlock the empty magazine from the mounting and give an indication that the one magazine is empty. The present invention is particularly adapted for use with the machine gun forming the subject of our co-pending application Serial No. 648,296, filed December 21, 1932.

In the drawings:

Fig. 1 is a fragmentary longitudinal vertical section (on line 1-! of Fig. 4) through a magazine operatively positioned in the mounting, showing the lower part of the magazine and adjacent parts of the gun;

Fig. 2 is a similar section through the upper portion of the magazine;

Fig. 3 is a longitudinal transverse section across the magazine on line 33 of Fig. 1;

Fig. 4 is a vertical transverse section of the magazine and the mounting on line G- l of Fig. 1;

The right-hand side of Fig. 5 is a partial vertical transverse section on line 5-5 of Fig. 1, and the left-hand side of Fig. 5 is a partial vertical transverse section on line 55' of Fig. 1;

Fig. 6 is an elevational detail view of the means for raising a magazine when empty;

Figs. 7 and 9 are fragmentary, vertical trans- Verse sections on lines T! and 9-9, respectively, of Fig. 1;

Fig. 8 is a' detail sectional View on line B-8 of Fig.

Fig. 10 is an elevational detail of a portion of the means for locking the mounting; and

Fig. 11 is a fragmentary transverse sectional View on line Hl l of Fig. 8.

Secured to the gun (not shown) in position to transfer cartridges from the magazine to the ramming mechanism is a feed plate 12 having a slot I3 through which the cartridges pass. Upon the upper face of the feed plate are two pairs of transverse ribs 14 and I5 whereof the upper faces are curved and sloped toward slot l3, as indicated at I6, the centers of curvature of such faces [6 lying upon the side of the longitudinal axis of slot I3 opposite from the respective face.

Mounted at the ends of feed plate l2 are forward bracket I! and after bracket I8 in which are journaled the trunnions H! of magazine cradle 20. As is shown in Figs. 4 and 5, the cradle 20 amended April 30, 1928; 370 0. G. 757) is open on its upper and lower edges and the walls thereof at the upper edge are folded over to strengthen the cradle and are outwardly flared to facilitate inserting magazines therein. A median wall 2| divides the cradle into two compartments, each of a size to receive one magazine, and has secured to its lower edge a bar 22 to reinforce the wall and provide a positionin stopfor the magazine. The upper edge of the cradle has formed in it at each end of each compartmenta slot 23 to receive a lug carried by the magazine, the slots at the forward ends being of different width from those at the after ends, and the cooperating lugs on the magazines being of corresponding widths to prevent placing the magazines in the cradle in the wrong position. In each forward lower corner of each compart ment a member 24 having an inwardly facing cam surface is secured to the cradle by means of a tab 25. passed through the cradle and secured thereto by upsetting or welding. These members 24- release the cartridge retaining device of the magazine when placed in the cradle, as Will be hereinafter described.

The forward end of bar 22 is expanded to form at each side asurface 26 that downwardly and outwardly slopes toward the opposite wall of the compartment, and a member having a surface 2'! that converges toward surface 26 is secured to the outer wall of each compartment, the two surfaces forming aguide for the projectile of a cartridge into the slot of the feed plate. Secured to the forward lower edge of the cradle 20 is a hardened steel plate 28 having in it notches 29 respectively disposed substantially medially of the transverse dimension of each magazine compartment to be engaged by a latch to hold the cradle in the feeding position.

A lug 38 having an apertured, laterally turned portion 3! is secured to each outer wall of cradle 20 substantially mid-way of the length thereof. A rod 32 is passed through the aperture in portion 3| and is prevented from dropping downwardly by a pin 33 therethrough. A spring 34' is disposedaround rod 32 and" is held undercompression between the head 35 of rod 32 and the upper end portion 36 of magazine lifter 37 which extends downwardly and has a laterally turned'portion 38 that passes through a slot in the wall of cradle 20 into the path of a magazine being inserted into theadjacent compartment. A housing 39 isfixed to cradle 20 to inclose the greater portion of magazine lifter 31 and keep it from swinging outwardly. When a magazine is pushed down into the compartment the lower edge of the magazine engages portion 38 and further compresses spring 34, and therefore, as soon as the force retaining the magazine in the cradle is released, it is lifted up by the expansion of spring 34.

Upon each side of the cradle adjacent its after end are secured two lugs 49 having axially aligned apertures therethrough in which a shaft 4| is mounted. To the forward end of each shaft 4| is secured a detent 42 having oppositely extending arms 43 and 44, the extremities of which arms may be moved into the adjacent magazine compartment through a slot 45 in the wall thereof when shaft 4| is rotated. The free end of arm 43 is substantially square to engage a locking lug upon a magazine and arm 44 is curved to cause the detent 42 to rotate shaft 4| when arm 44 is contacted by a magazine that is being withdrawn from the cradle. The after end of each of the shafts 4| carries a locking element 46, said looking elements extending toward each other across the after end of the cradle and each has in the edge thereof that faces the other, two V-shaped notches 41 and 48, the adjacent walls of the two notches intersecting to form a pointed tongue 49 between them, the distance between the outer extremities of the walls of notch 43 being greater than the corresponding dimension of notch 41. Between locking elements 46 a member 50 having a polygonal passage therein is secured to the cradle and is disposed with the axis of the opening therethrough intersecting the two shafts 4|, and in that opening are two sears 5| whereof the outer ends are shaped and disposed to engage in notches 41 and 48, a spring 52 being placed under compression between the two sears to urge them outwardly. Mounted upon pivots 53 carried by lugs 54 secured to the edges of after bracket |8 are two trip members 55, the lower arm 56 of each of the trip members being disposed to contact the adjacent locking element 46 under certain conditions of relative movement hereinafter to be explained, and the upper arm 5'! of each trip member being disposed to engage a stop 58 secured to the after bracket l8, the spring 59 connected to both the trip members under tension tending to hold the trip members against their respective stops.

Since trip members 55 are mounted on the bracket and the locking elements 46 are carried by cradle 29, it is evident that when cradle 29 swings on its trunnions there will be relative movement between the trip members and the locking elements.

Referring now to Fig. 8, it will be noted that the bottom of cradle is swung toward the left, that the left-hand sear 5| engages notch 41 of the coacting locking element 46, that the arm 43 of detent 42 on the left-hand side is outside of the cradle 20, and that arm 56 of the left-hand trip member 55 lies between the two locking elements; also, that the right-hand sear 5| is in notch 48 of the coacting locking member, the lower arm 43 of detent 42 on that side extends within the cradle and that arm 56 of the right-hand trip lies outside the adjacent locking member, these being the positions of the several parts when cartridges are being fed from a magazine in the right-hand compartment of cradle 20 as viewed in Fig. 8, the magazine in the left-hand compartment having just been emptied and the arm 43 of detent 42 disengaged therefrom but the empty magazine not yet withdrawn. In the removal of the left-hand magazine the curved arm 44 of detent 42 on that sidewillbe contacted by a portion of the magazinc and shaft 4| will be rotated, which will rotate locking element 46 also and cause the coacting sear 5| to ride up on the tongue 49 and as soon as the edge of the sear has passed the apex of tongue 49 the action of the sear upon the sloping face of notch 48 will be to continue the rotation of shaft 4| until the sear is seated in the bottom of notch 48, at which time the arm 43 on the lefthand side will occupy the same relative position as does the like arm 43 on the right-hand side.

Insertion of another magazine into the lefthand compartment will cause the arm 43 to be moved out but owing to the relatively greater Width of the notch 48, the sear 5| will not be moved over the apex of tongue 49 and the arm 43 will be rotated back into locking position by the action of the sloping face of the sear against the sloping face of notch 48. When the bottom of cradle 29 is moved toward the right, the arm 56 of trip member on the right-hand side will engage the uppermost portion of locking member 46 on the right-hand side and rotate shaft 4| until. the apex of tongue 49 has passed the edge of sear 5| after which the sear will continue the rotation of shaft 4| until the sear is seated in the notch 41 and the magazine in the right-hand compartment will be unlocked. It Will be observed that rotation of trip member 55 on the right-hand side under the conditions just mentioned will be prevented by contact of the arm '51 against stop 58 but that, on the left-hand side, the contact of locking element 43 with the trip on that side will rotate the trip member on its pivot and stretch spring 59, but as soon as the locking member has cleared the trip, the arm 51 of the left-hand trip Will be moved back aaginst its stop 58,

The magazine consists of a box 60 of relatively light metal with reinforcing ribs 6| formed in the sides thereof and is completely closed except at its lower edge which is left open for the passage of cartridges into and from the magazine. Lugs 62 and 63 on the forward and after ends, respectively, of the magazine fit in the slots 23 in cradle 29 and are of different widths to prevent improper placing of the magazine as above explained. Seated against the closed upper edge of the magazine are two springs 64 and 65, the channel tie members 66 being secured to approximately corresponding turns of the two springs to prevent undue spreading and lateral fiexion of the springs. The two springs 64 and may be wound opposite to each other if desired. The lower ends of the springs bear against a feed plate 61 that contacts the base of the cartridge case and has a member 58 projecting therefrom to contact the cartridge at another point and thus apply the force of the springs 64 and 65 to feed the cartridges from the magazine. The up-turned portions 69 at the after'end of the feed plate prevent lateral tilting of the plate; the flanges 79 extending therefrom engage another portion of the magazine when empty and prevent the feed plate from being forced out of the magazine by the springs; and the downwardly extending lug 1| contacts the cradle release latch When the magazine has been emptied. The side walls of the magazine are grooved as indicated at 12 to engage the rim of the cartridge case and prevent forward movement of the cartridges in the magazine while two members '33 on each side wall serve as a guide for the spring 54 and'also hold the projectile ends of the cartridges centered in the magazine.

The cartridges are held in the magazine by the forward retainers l4 and after retainers 15. The

gamma retainers of the former pair are disposed opposite each other and are secured at their upper ends to-the inner face of each side wall of the magazine. Each retainer M consists of a flat strip of resilient metal that has adjacent its lower end a folded over portion forming a toe E6 to engage a cartridge and thence extends outwardly through a slot in the magazine wall, and the end thereof is up-turned as shown at T! to contact the magazinewall and prevent displacement of the retainer from the slot in the magazine wall. The after retainers l5 are secured to the outer face of the magazine wall with riveting blocks 13 interposed between the retainer strip and the wall and extend downwardly through slots in the intervening ribs to a point adjacent the open edge of the magazine where they are laterally folded to form a toe 19 that extends through a slot in the magazine wall into position to engage a cartridge.

A guide housing 8!] is provided on each magazine side wall adjacent the opening of the magazine and may be made of either the metal of the magazine suitably bent or a separate piece shaped and secured to the magazine. Slidably disposed in the guide housing on each side is a retainer bar 8! having in it a slot 52 that may be brought in registry with the after retainer 75 and a slot 83that may likewise be moved to registry with the forward retainer it which will permit the retainers to be sprung outwardly by the force exerted thereon due to the springs as and 6-5 and allow the feeding of cartridges from the magazine. Adjacent the slots 82 and 83 are blocks 84 and 85 on the release bars 8! which, when moved opposite the respective retainers, prevent withdrawing movement of the retainers and hold the cartridges in the magazine. Near the longitudinal center of each release bar two spaced cuts are madein one edge thereof and the portion between those cuts is bent laterally as indicated at 85, thus forming substantially a cut-out portion in the release bar. A block 8? is fixed to each side wall of the magazine to extend into the said cut-' release bar projects from the guide housing but when the magazine is placed in the cradle the members M in the cradle contact the projecting ends of the release bars and move the bars back until the slots 82 and B3 register with the cartridge retainers and thus the cartridges may be moved out of the magazine by the pressure of the feed springs 6d and B5. The lower edge of the magazine is reinforced at both ends by U- shaped members 89.

The cradle is held in the feeding position by the engagement of notches 29 with the free end of latch so whereof the outer end is pivoted in the base of the forward bracket IT and which free end is urged upwardly by a spring 9!. Slot 9?. is formed in the free end of latch 99 and in this slot there is pivotally mounted a lever 93 having an arm 9 3 that extends into position to be contacted by the lug H on magazine feed plate and an arm 95 extending oppositely thereto and having on its upper edge a cam shaped face 96. It will be observed in Fig. 1 that when the cradle is locked, cam face 96 bears against a portion of forward bracket I! that is substantially verticallyabove the pivot of lever 93, thus giving-a very 6, high mechanical advantage for starting the downward movement of latch 9% but as the rotation-of lever 93 on its pivot continues, the point of contact of face 95 with bracket l1 moves farther away from the pivot, giving a lower mechanical advantage but an accelerated rate of movement of the free end'of latch 90.

To load the magazine it is placed in a fixture that moves the release bars 8| to bring the slots 82 and 83 into registry with the respective cartridge retainers and the cartridges are then inserted in the magazine by pressing them against the retainers which are thus sprung aside and the cartridge is admitted to the magazine; when full, the magazine is removed from the fixture whereupon the springs 88 move the release bars forward and lock the retainers against withdrawing movement. When the magazines are placed in the cradle, the arms 33 of detent 2 engage the locking lugs 91 and hold the magazine firmly in operative position and a full magazine cannot be removed from the cradle without releasing the detent 62 from engagement with the locking lug 9? thereon.

In use, two full magazines will be placed in the cradle and the cradle swung on it trunnions to position one of them above the slot I 3 in feed plate 52. Since, as above explained, the release bars are moved away from the position in which they look the cartridge retainers as soon as the magazine is placed in the cradle, the cartridges from the magazine in feeding position will then be free to feed into the gun. The lowermost cartridge in the other magazine will bear against the ribs H3 and F5 on that side of the feed plate and due to the curvature and slope of the face It the pressure of the feed springs in that magazine, transmitted through the cartridges, will exert a force upon those ribs that will have a component tending to swing the cradle to bring that magazine into feeding position. As soon as the first magazine is emptied, the lug H on the feed plate therein will contact arm 94 of lever 93 and release the latch 90, thus permitting the force component mentioned to swing the cradle and bring the full magazine into the feeding position. As heretofore explained, the swing of the cradle brings the arm 56 of trip member 55 on that side of the cradle containing the empty magazine into contact with the locking element 65 on that side which, through shaft il, rotates the detent 42 and disengages the arm 43 of that detent from the locking lug 9? of the magazine, whereupon the magazine lifter 33 is moved by the spring 35 and the empty magazine is moved upwardly in the cradle to indicate that it is empty. As the empty magazine is withdrawn from the cradle the guide housing contacts the curved arm (it of the detent i2 and rotates the shaft ll suificiently to move the sear 5! over the apex of tongue 69 into the notch 48 and the action of spring 52 and sear 5| completes the movement of arm 43 into the locking position. When a full magazine is inserted it contacts the arm 43 of the detent and moves it aside, thus rotating the shaft il, but inasmuch as the sear 5i is not moved out of the notch 48, the arm 53 of detent 42 is rotated back into engagement with the locking lug 91 by the action of sear 5! and spring 52.

The herein described invention may be manufactured and used by or for the Government of the United States of America for governmental purposes, without the payment of any royalties thereonl- We claim: s

1. A cartridge magazine, comprising a box of thin metal open on one edge and having its sides reinforced by being ribbed, U-shaped reinforcing members secured to the ends thereof adjacent said open edge, a positioning lug on each end, the two lugs being of different width, a lug on one side engageable by a locking detent to hold the magazine in operative position, two forward retainers disposed opposite each other and secured at their upper ends to the inner face of the side of the box, the lower portion of each retainer being folded inwardly to form a toe to engage a portion of a cartridge and extending thence outwardly through a slot in the box wall and having its end up-turned parallel to the outer face of said wall, two after retainers disposed opposite each other and secured at their upper ends to the outer face of said wall and having their lower ends folded and laterally turned to extend toward each other through slots in said wall, a guide housing along each side wall adjacent said open edge, a release bar slidable in each of said housings, each of said bars having slots positioned to be brought into registry with said retainers and a cut-away portion, a fixed block extending into each of said cut-away portions, a spring in each of said cutaway portions having one end abutting the fixed block therein and the other end abutting the release bar to urge said bar forwardly and cause said bar normally to hold said retainers against outward swing, two spaced apart coiled springs disposed with an end of each against the inner face of the box opposite said open edge, means tying together a plurality of substantially corresponding turns of said springs, a feed bar disposed against the other ends of said sprin s to move cartridges out of said boxhaving a downwardly extending latch-releasing lug at its forward end and two spaced apart guides for the forward one of said springs secured t the inner face of each of the side walls of said box.

2. In combination with forward and after brackets secured to a gun, a magazine cradle having compartments to receive two magazines, said compartments being open on their upper and lower edges and there being in each compartment a slot in the upper edge of its forward end and a slot of different Width in the upper edge of its after end, axially aligned trunnions on the two ends of the cradle journalled in said brackets, a pair of lugs on each side of said cradle adjacent its after end having aligned bores therethrough, a shaft journalled in each pair of lugs, fixed to the forward end of each shaft a detent having a downwardly extending arm with a squared locking end to engage a locking lug on a magazine in said cradle and an upwardly extending arm having a curved tripping end, said ends being movable into the adjacent compartment through a slot in the wall of said cradle, fixed on the after end of each of said shafts a locking element, those ends of said elements facing each other each havin two V-shaped notches separated by an inverted V-shapcd tongue, a member having a passage therethrough fixed to said cradle between said elements, two sear members slidably mounted in said passage and having their outer ends shaped and disposed to engage said V-shaped notches, a spring between said sears to urge them outwardly, a pivoted trip member mounted on the after bracket adjacent each of said locking elements to contact and rotate said elements under certain conditions of relative movement therebetween to release said locking end from said lug, a spring connected to said trips to draw them toward each other, stops on the after bracket to limit the movement of said trips toward each other, a member secured to the lower forward edge of said cradle having in it a locking notch in each compartment, a pivoted latch under the forward bracket engageable with said locking notches and releasable therefrom by the action of a member in a magazine when the magazine is empty, and means acting in each of said compartments to lift upwardly a magazine therein when unlocked from the cradle after being emptied.

3. In combination with a gun, forward and after brackets mounted thereon, a cartridge magazine, a cradle having compartments to receive two such magazines, axially aligned trunnions on said cradle journalled in said brackets, inter-engaging parts on said magazine and said cradle to insure proper positioning of the magazine in the cradle, means to lock the magazine in the cradle, means operable by swinging of said cradle on its trunnions to release said locking means, means to lock said cradle against swinging, means in said magazine to release said cradle locking means when the magazine is empty, means to retain cartridges in said magazine, means carried by said cradle to release said retaining means to permit passage of cartridges from the magazine when operatively positioned in the cradle, and means carried by the cradle to be engaged by a magazine and placed under stress when the magazine is placed in the cradle and by release of said stress to move the magazine upwardly when the magazine is unlocked from the cradle.

4. A cartridge magazine, comprising a box open on one edge, means to move cartridges out of said box, and means normally to retain cartridges in said box including two forward retainers disposed opposite each other and secured at their upper ends to the inner face of the side of the box, the lower portion of each retainer being folded inwardly to form a toe to engage a portion of the cartridge and extending thence outwardly through a slot in the box wall and having its end up-turned parallel to the outer face of said wall, two after retainers disposed opposite each other and secured at their upper ends to the outer face of said wall and having their lower ends folded and laterally turned to extend toward each other through slots in said wall, a guide housing along each side wall adjacent said open edge, a release bar slidable in each of said housings, each of said bars having slots positioned to be brought into registry with said retainers and a cut-away portion, a fixed block extending into each of said cut-away portions, and a spring in each of said cut-away portions having one end abutting the fixed block therein and the other end abutting the release bar to urge said bar forwardly and cause said bar to hold said retainers against outward swing, said release bars being movable backwardly to bring the slots therein in registry with said retainers and so permit the retainers to be swung outwardly to deliver cartridges from the magazine.

5. In combination with a gun, forward and after brackets mounted thereon, a magazine cradle swingably mounted between said brackets, a, locking plate carried by the forward lower edge of said cradle having locking notches therein, a latch pivoted at one end to said forward bracket and having its free end disposed to engage said locking notches, a lever pivoted in the free end of said latch having an arm extending into said cradle and an oppositely extendin arm with a cam-like face on its upper edge to contact a por- 9 tion of said bracket, a resilient means to urge said free end of said latch upwardly, a shaft rotatably mounted on each side of said cradle ad jacent its after end, a detent having a locking arm to engage a portion of said magazine and an oppositely extending curved tripping arm on the forward end of each said shaft, a locking element on the after end of each shaft, those faces of said elements that are turned toward each other having each two l-shaped notches with the adjacent walls of the notches intersecting, a member having a passage therethrough mounted on said cradle between said elements, two sear members slidably mounted in said'passage having their outer ends shaped and disposed to engage said notches, a spring between said sears to urge them outwardly, a pivoted trip member mounted on the after bracket adjacent each of said locking elements to contact and rotate said elements under certain conditions of relative movement therebetween thereby to disengage said locking arm from said portion, a spring connected to said trips to draw them toward each other, stops on the after bracket to limit the movement of the trips toward each other and means at the forward edge of said cradle adjacent said open edge to release a cartridge retaining device of a magazine when positioned in said cradle. V V

'6. In combination with a gun, forward and after brackets mounted thereon, a magazine cradle swingably mounted between said brackets, a locking plate carried by the forward lower edge of said cradle having locking notches therein, a latch pivoted at one end to said forward'bracket and having its free end disposed to engage said locking notches, a lever pivoted in the free end of said latch having an arm extending into said cradle and an oppositely extending arm with a cam-like face on its upper edge to contact a portion of said bracket, and resilient means to urge the said free end of said latch upwardly.

'7. In combination with a gun, forward and after brackets mounted thereon, a magazine cradle swingably mounted between said brackets, a locking plate carried by the forward lower edge of said cradle having locking notches therein, a latch pivoted at one end to said forward bracket and having its free end disposed to engage said locking notches, a lever pivoted in the free end of said latch having an arm extending into said cradle and an oppositely extending arm with a cam-like fac on its upper edge to contact a portion of said bracket, resilient means to urge said free end of said latch upwardly, a

magazine in said cradle and means in said magazine to depress said lever and release the latch when the magazine is empty.

8. In combination with a gun having a longitudinally slotted feed plate and a plurality of curved faces transverse to the slot therein, the center of curvature of each face being on the opposite side of the slot from the face, forward and after brackets mounted adjacent said plate, a cradle having compartments for two magazines swingably mounted between said brackets, two cartridge magazines in said cradle, means to lock said cradle in position for either magazine to feed into said slot, means in each magazine to release said locking means when the magazine is empty thereby permitting the pressure of the lowermost cartridge in the other magazine exerted upon said curved faces in contact with said cartridge to swing said cradle, means to lock each magazine in the cradle, means actuatable by swinging of to be fed from the magazine.

9. In combination with a gun having a longitudinally slotted feed plate and a plurality of curved faces transverse to the slot therein, the center of curvature of each face being on the opposite side of the slot from the face, forwardand after brackets mounted adjacent said plate, a cradle having compartments for two-magazines swingably mounted between said brackets, two cartridge magazines in said cradle,-means to lock said cradle in position for either magazine to feed into said slot, and means ineach magazine to release said locking means when the magazine is empty thereby permitting the pressure of the lowermost cartridge in the other magazineexerted upon said curved faces in contact with said cartridge to swing said cradle.

10. In combination with a gun having a longitudinally slotted feed plate and a plurality of curved faces transverse to the slot therein, the center of curvature of each face being on the opposite side of the slot from the facefforward and after brackets mounted adjacent said plate, a cradle having compartments for two magazines swingably mounted between said brackets, two cartridge magazines in said cradle, means to lock'said cradle in position for either magazine to feed into said slot, means in each magazine to release said locking means when the magazine is empty thereby permitting the pressure of the lowermost cartridge in the other magazine exerted upon said curved faces in contact with said cartridge to swing said cradle, means to lock each magazin in the cradle, and means actuatable by swinging of said cradle to release the magazine locking means.

11. In combination with a gun having a longitudinally slotted feed plate and a pluraltiy of curved faces transverse to the slot therein, the center of curvature of each face being on the opposite side of the slot from the face, forward and after brackets mounted adjacent said plate, a cradle having compartments for two magazines swingably mounted between said brackets, two cartridge magazines in said cradle, means to lock said cradle in position for either magazine to feed into said slot, means in each magazine to release said locking means when the magazine is empty thereby permitting the pressure of the lowermost cartridge in the other magazine exerted upon said curved faces in contact with said cartridge to swing said cradle, means to lock each magazine in the cradle, means actuatable by swinging of said cradle to release the magazine locking means,

- and means carried by said cradle having a portion engageable by a magazine being inserted in the cradle and an element connected thereto to store up energy imparted thereto by movement of said portion due to insertion of the magazine to raise the magazine when unlocked from the cradle.

12. In combination with a gun, a magazine cradle swingably mounted on said gun, a shaft rotatably mounted on each side of said cradle adjacent its after end, a detent having a locking arm to engage a magazine in the cradle and an oppositely extending curved tripping arm on the forward end of each shaft, a locking element on the after end of each shaft, those faces of said elements that are turned toward each other having'each two V-shaped notches with the adjacent walls of the notches intersecting, a member having a passage therethrough mounted on the eradle between said elements, two sear members slidably mounted in said passage having their outer ends shaped and disposed to engage said notches,

a spring between said sears to urge them outwardlyl a pivoted trip member mounted on a fixed member adjacent each of said elements to contact and rotate said elements under certain conditions of relative movement therebetween thereby to disengage said locking arm from said magazine, a spring connected to said trips to draw them toward each other, and stops on the said fixed member to limit the movement of said trips toward each other.

13. In combination with a gun, forward and after brackets mounted thereon, a cartridge magazine, a cradle having compartments to receive two such magazines, axially aligned trunnions on said cradle journalled in said brackets, means to lock the magazine in the cradle, means operable by swinging of said cradle on its trunnions to release said locking means, means to lock the eradle against swinging, mean in said magazine to release said cradle lockin means when the magazine is empty, means to retain cartridges in said magazine, and means carried by said cradle to release said retaining means to permit passage of cartridges from the magazine when operatively positioned in the cradle.

14. In combination with a gun, forward and after brackets mounted thereon, a cartridge magazine, a cradle having compartments to receive two such magazines, axially aligned trunnions on said cradle journalled in said brackets, means to lock the magazine in the cradle, means operable by swinging of said cradle on its trunnions to release said locking means, means to lock the cradle against swinging, and means in said magazine to release said cradle locking means when the magazine is empty.

15. In combination with a gun, forward and after brackets mounted thereon, a cartridge magazine, a cradle having compartments to receive two such magazines, axially aligned trunnions on said cradle journalled in said brackets, means to lock the magazine in the cradle, and means operable by swinging of said cradle on its trunnions to release said locking means.

GEORGE A. CHADWICK.

PAUL W. BURK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

